How does soluble fiber affect cholesterol levels?

• A. Soluble fiber raises LDL cholesterol.
• B. Soluble fiber lowers LDL cholesterol by binding bile acids and reducing cholesterol absorption.
• C. Soluble fiber has no effect on cholesterol.
• D. Soluble fiber only affects HDL.

Answer: (B)

Soluble fiber lowers LDL cholesterol. It forms a gel in the gut that binds bile acids, which are produced from cholesterol for digestion. When these bile acids are bound, they’re excreted instead of reabsorbed, so the liver must pull more cholesterol from the blood to synthesize new bile acids. This process reduces circulating LDL cholesterol. Soluble fiber also reduces the absorption of dietary cholesterol and may promote gut bacteria production of short-chain fatty acids that can further dampen hepatic cholesterol synthesis. Foods high in soluble fiber include oats, barley, legumes, and psyllium.